What Causes Sudden Nausea and Vomiting?

The abrupt onset of nausea and vomiting can disrupt your day without warning, leaving you feeling miserable and searching for relief. These symptoms, while common, can signal anything from a minor digestive upset to a more serious underlying condition requiring immediate medical attention. Understanding the potential causes can help you determine whether your symptoms warrant a trip to the emergency room or if home remedies might suffice.

Common causes of nausea and vomiting include:

• Food poisoning
• Viral gastroenteritis (stomach flu)
• Migraine headaches
• Medication side effects
• Vestibular disorders affecting your inner ear and balance
• Pregnancy
• Intense pain or emotional distress

Nausea and sudden vomiting causes concern for both parents and adults, and determining the root cause quickly can make all the difference in your treatment and recovery. Don’t hesitate to seek medical attention at a Complete Care freestanding ER location, especially if symptoms are severe or accompanied by other concerning signs like chest pain, severe headache, or dehydration.

Food poisoning

Food poisoning typically strikes suddenly, often within hours after consuming contaminated food. The hallmark symptoms include:

• Intense nausea followed by vomiting and diarrhea
• Rapid onset of symptoms
• Abdominal pain ranging from mild cramping to severe discomfort
• Possible fever and chills

Recovery from food poisoning generally occurs within 1–3 days without specific treatment. However, severe dehydration symptoms may develop quickly in vulnerable individuals like children and the elderly, as fluid loss can be significant with persistent vomiting and diarrhea. 

If you’re unable to keep fluids down for more than 24 hours or experience symptoms of severe dehydration (extreme thirst, dry mouth, little or no urination, severe weakness), seeking medical attention for IV fluids for dehydration may be necessary.

Viral gastroenteritis (stomach flu)

Viral gastroenteritis, commonly known as the stomach flu, develops when a virus infects your intestines, triggering inflammation that leads to sudden vomiting and diarrhea. When considering stomach flu vs. food poisoning, stomach flu develops gradually over 24-48 hours, while food poisoning comes on quickly. It’s also highly contagious, spreading through close contact or contaminated surfaces, often affecting entire households, schools, or workplaces.

While vomiting and diarrhea are the most recognizable symptoms, stomach flu may also present with: 

• Low-grade fever
• Headache
• Muscle aches
• Extreme fatigue 

Symptoms generally persist for 1-3 days, though some viruses like norovirus can cause illness for up to a week. Rotavirus, once a common cause of nausea and gastroenteritis in children, has become less prevalent due to routine childhood vaccination. 

Flu treatment focuses on preventing dehydration through small, frequent sips of clear fluids, progressing to bland foods as tolerated. If symptoms last more than three days or are accompanied by bloody stools, severe abdominal pain, or inability to keep fluids down, a medical evaluation is recommended.

Continue reading: When should you go to the doctor for the flu?

Migraine headaches

Migraines can cause nausea without vomiting, often before head pain starts. In some cases, like silent migraines, nausea can happen without a headache forming at all. In fact, many migraine sufferers report a distinct feeling that “something isn’t right” hours before full symptoms develop, along with visual disturbances like flashing lights, blind spots, or zigzag patterns known as aura.

What distinguishes migraine-related nausea from other causes is its association with neurological symptoms and triggers. Stress, certain foods, hormonal changes, sleep disruptions, and environmental factors like bright lights or strong odors can all trigger an attack. 

The nausea typically worsens with movement and is relieved by lying in a dark, quiet room. Medications that target both the headache and digestive symptoms, taken at the first sign of migraine, can significantly reduce severity. For those with frequent migraines, preventive treatments including medications, stress management techniques, and trigger avoidance can reduce the frequency and intensity of episodes.

Medication side effects

Medication-induced nausea can occur either immediately after taking a drug or develop gradually with continued use. Certain medications are notorious for triggering digestive upset, including many: 

• Antibiotics
• Opioid pain relievers
• Chemotherapy drugs
• Non-steroidal anti-inflammatory drugs (NSAIDs)

The timing of symptoms often provides clues — nausea appearing within minutes to hours after taking a medication suggests a direct effect, while symptoms developing days later might indicate an accumulated side effect or developing intolerance.

If you find yourself wondering, “Why do I feel suddenly sick and nauseous randomly?” after starting a new medication, consider whether the symptoms correlate with dosing times. Taking medications with food (unless contraindicated) can reduce stomach irritation, as can spacing doses throughout the day rather than taking them all at once. 

Never discontinue prescription medications without consulting your healthcare provider, as sudden stopping can sometimes trigger dangerous withdrawal effects or disease flare-ups. Your doctor may be able to adjust your dosage, recommend a different medication in the same class, or prescribe anti-nausea medication to take alongside your treatment.

Vestibular disorders affecting your inner ear and balance

Vestibular disorders create a distinct type of nausea that’s triggered or worsened by movement and often accompanied by vertigo, the false sensation that you or your surroundings are spinning. Conditions like benign paroxysmal positional vertigo (BPPV), Ménière’s disease, vestibular neuritis, or labyrinthitis can trigger sudden episodes where the room seems to spin, accompanied by intense nausea, vomiting, and difficulty maintaining balance.

You might notice that certain head positions or movements predictably trigger symptoms, or experience accompanying ear symptoms like ringing, fullness, or hearing changes. Some people mistake vestibular-triggered nausea for acid reflux pain in the upper abdomen when the true source is their inner ear. 

Diagnosis is done by an ENT or neurologist through specialized tests. Treatment depends on the condition and may include exercises, medication for symptom relief, or, in some cases, surgery. For BPPV, specific head maneuvers can quickly reposition inner ear crystals and provide immediate relief.

Pregnancy

Pregnancy-related nausea, or “morning sickness,” can happen anytime and usually starts around week six, easing by the end of the first trimester — though some experience it for longer. It may be constant or triggered by smells, foods, or an empty stomach. While the exact cause is unclear, rising hormone levels, especially hCG and estrogen, are key factors, with symptoms peaking when hCG is highest.

Most women can manage pregnancy nausea with small, frequent meals, avoiding trigger foods, and using ginger for relief. However, some develop hyperemesis gravidarum, a severe form with constant vomiting, weight loss, and dehydration, sometimes requiring hospitalization.

If you’re experiencing severe nausea and vomiting during pregnancy, especially if you’re unable to keep fluids down, contact your healthcare provider promptly, as both the mother and developing baby may need support.

Intense pain or emotional distress

The body’s response to severe pain or acute emotional distress can manifest physically through the activation of the vagus nerve, triggering nausea and sometimes vomiting even when no digestive issue exists. This phenomenon, known as a vasovagal response, occurs when the nervous system’s balance shifts suddenly, causing blood pressure to drop, heart rate to slow, and digestive processes to change. 

This cause can be confusing because the nausea may seem random and unrelated to its trigger. If you feel unexplained nausea during or after stressful events or pain, this response could be the cause. The symptoms usually go away once the trigger or pain is resolved, though some effects may last.

For those who experience nausea triggered by anxiety or emotions, cognitive behavioral therapy, and stress management techniques can help lessen how often and how strongly these reactions occur. Identifying emotional triggers is a key step in understanding one of the most common but often unclear causes of nausea.

What helps with nausea and vomiting?

To manage nausea and vomiting effectively, it’s important to treat the cause, but there are also general strategies that can help. These include:

• Staying hydrated with small sips: Instead of gulping large amounts of fluid, take tiny sips of clear liquids like water, diluted sports drinks, or clear broth every 15 minutes.
• Trying the BRAT diet: Bananas, rice, applesauce, and toast are gentle, binding foods that can ease digestive problems.
• Ginger in various forms:Studies support ginger tea, candies, or capsules as effective natural anti-nausea remedies.
• Aromatherapy with peppermint or lemon essential oils: Inhaling these scents can reduce nausea intensity for many people without introducing anything to the stomach.
• Avoiding strong smells and flavors: Even normally pleasant aromas can trigger or worsen nausea, so opt for room-temperature foods with minimal odor.
• Resting in a semi-upright position: Lying completely flat can worsen symptoms, while a slightly elevated position helps keep stomach contents where they belong.
• Acupressure at the P6 point: Applying pressure about three finger-widths above the inner wrist crease may alleviate nausea.

While these measures can help with most nausea and vomiting, if symptoms persist or you notice warning signs like the ones listed below, don’t wait to seek medical attention. A healthcare professional can decide if prescription medications, IV fluids, or other treatments are needed to address both your symptoms and their cause.

When should you go to the ER for nausea and vomiting?

While most cases of nausea and vomiting resolve with home care and time, certain symptoms signal a medical emergency requiring immediate attention. Emergency symptoms include:

• Unable to keep any fluids down for 24 hours
• Blood in vomit or stool
• Severe, sudden headache with vomiting
• Abdominal pain that is severe or localized
• Signs of severe dehydration
• Chest pain or difficulty breathing with nausea
• High fever with vomiting (>102°F)

If you notice warning signs, don’t wait to get emergency care. Complete Care’s standalone emergency facilities offer the same care as hospital-based ERs, with shorter wait times. Our emergency-trained doctors can diagnose the cause and provide treatment, including medication, hydration, or surgery if needed.

Don’t stomach severe symptoms alone. Complete Care has your back!

While nausea and vomiting can be common experiences, they should never be ignored when they present with concerning symptoms or persist after home remedies. 

At Complete Care, we understand how quickly these symptoms can escalate from uncomfortable to unbearable, which is why our teams are ready to provide prompt, compassionate care at our convenient locations across Texas and Colorado. With freestanding emergency facilities in Austin, Corpus Christi, Dallas/Fort Worth, East Texas, Lubbock, San Antonio, and Colorado Springs, expert help is never far away, no matter when symptoms strike. 

Our emergency-trained physicians and state-of-the-art diagnostic capabilities ensure you’ll receive the highest standard of care without the typical ER wait times. 

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